Investment grade refers to credit ratings assigned to corporate or government bonds by rating agencies such as Moody's, Standard & Poor's, and Fitch Ratings. These ratings signify the issuer's ability to meet its financial obligations, including interest and principal payments on the bonds, and indicate the likelihood of default.

An investment-grade rating typically ranges from AAA to BBB- for Standard & Poor's and Fitch, and from Aaa to Baa3 for Moody's. Bonds with ratings of BBB- or higher are considered investment grade and are generally considered to be lower risk and more stable investments than bonds with lower ratings.

In the financial industry, investment-grade bonds are often used in fixed-income portfolios, and investors may seek to diversify their portfolios by investing in a range of investment-grade bonds issued by various corporations and government entities. Investment-grade bonds typically offer lower yields than high-yield or junk bonds, but their stability and lower default risk make them attractive to many investors.

Furthermore, investment-grade ratings may have strategic importance for issuer firms and governments. For example, a higher credit rating may provide a cheaper cost of capital, more favorable borrowing terms, access to a larger pool of investors, and higher investor confidence. This could lead to additional investments, increased goodwill, and a better perception of the issuer's creditworthiness.